This invention generally relates to optical transport systems, optical couplings to connect equipment and optical pathways therein, and more particularly an apparatus and system for optimizing and managing said connections, to provide access to an optical path and the protection of data throughput thereon.
In optical transport systems is it desirable to eliminate optical connectors from the optical signal path in general to reduce the costs incurred by the requirement for the use of optical signal compensation and regeneration equipment. It is also desirable to allow systems to operate at higher optical powers which allows more data to travel greater distances. The elimination of connectors may be achieved by splicing the fibers to effect the desired optical couplings. Once equipment or optical components have been connected by way of physical splices of the optical fiber, however, it becomes impractical to disconnect the fiber to gain access to the optical data path for any reason.
One reason access to an optical data path is desirable, is that it allows for the assessment of the quality and health of a span of fiber with the use of optical test equipment such as an Optical Time Domain Reflectometer (OTDR). An OTDR, once optically coupled to a span of fiber, is used to measure the quality and health of the span of fiber by producing a series of high optical power pulses and measuring the light reflected and scattered back from the span of fiber. The high optical power pulses output by the OTDR, however, will interfere with any data on the fiber, causing bit errors.
It is therefore strongly desirable to engineer a solution which effects the elimination of optical signal connectors along the optical signal path and yet allows for access to that optical path in a manner which also protects the data from interference from equipment utilizing said access. Such a solution, for example, would allow system fiber to be measured with an OTDR during installation and configuration while preventing high optical power OTDR signals from inundating the system fiber when data is present.
This invention provides the desired solution by providing an optical data throughput protection switch which allows access to an optical path when there is no data traffic on the path, and denies access to the optical path when data is present, thereby protecting the data throughput.
The optical data throughput protection switch consists of a controllable switch and a controlling means. The controllable switch is optically coupled to a first optical path and also optically coupled to the termination of a second optical path. The controllable switch is controlled by the controlling means and functions to enable and disable optical coupling between the termination of the second optical path and the first optical path. The result is that the data throughput on the first optical path can be controllably protected from optical signals of the second optical path.
The optical data throughput protection switch simultaneously addresses both the desirability to reduce the number of optical connectors along an optical path while enabling access to that path. The optical data throughput protection switch, once spliced into the first optical path, does not require the use of connectors along the optical path, allowing for operation at higher powers. Access to the path, which would otherwise be impracticable in a spliced system, is attained by providing controlled access to the path through a controllable switch. Access to the optical path is controlled by attenuating, blocking or otherwise disabling optical signals of the second path from propagating to the first path when data is on the first path, and allowing optical signals of the second path onto the first path when there is no data traffic on the first path. In one embodiment the controlling means are input with traffic information of the first optical path, to decide when to allow and when to disable optical coupling between the first and second optical paths. In another embodiment the controlling means controls the controllable switch using an externally set software state variable, which allows for manually enabling or disabling optical coupling between the first and second optical paths. In this way users or high level systems can manually control the controllable switch. In another embodiment the controlling means has a first mode of operation in which it uses traffic information of the first optical path to decide when to allow and when to disable optical coupling between the first and second optical paths, and a second mode of operation in which it uses the externally set software state variable to control the controllable switch.
The optical data throughput protection switch, when used in conjunction with an OTDR optically coupled to the second optical path allows the system fiber to be measured with an OTDR during installation and configuration while preventing high power OTDR signals from inundating the system fiber when data is present.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.